In response to Japan’s current regional disparity, much attention has been given to the possibility of revitalizing her peripheral regions through in-migration of retirement-age people. Although population geographers have not viewed such internal migration that is common in Japan, it merits careful scrutiny in the current context of the country’s population trends. This article identifies such migration by analyzing the net-migration rate of people aged 60?64 years by prefecture/municipality and their migration schedules during the period 2005-2010. This work’s findings can be summarized as follows. Extensive human flows of the above age class were confirmed from Japan’s three largest metropolitan areas（Tokyo, Osaka, and Nagoya）to peripheral prefectures, almost all of which have positive netmigration rates. The spatial pattern of these rates suggests that while retirement migration to eastern Japan involves only U-turns（return migration to hometowns）, such migration to western Japan generally consists of both U-turns and I-turns （migration unrelated to hometowns）. The examination reported here at the municipal level clarified primary municipalities as destinations in three parts: Hokkaido, the Kanto and Chubu regions, and the Kinki region along with those regions farther west. Especially noteworthy is that the municipalities located in the third part are largely rural/mountain areas and islands to which retirees are attracted by favorable conditions, including amenity-rich environments. The current findings convincingly suggest that internal retirement migration does in fact exist, plays an important role in den’en-kaiki（migration to the countryside）, and mitigates the problem of mono-polar concentration in Tokyo.